Unexpected Find

[Ratmosphere]

While gathering supplies in the woods for beetle breeding, I found something spectacular on a branch with leaves. It's a cocoon! I'm pretty sure that there's a big moth inside. This totally made my Monday.

(Photos deleted.)

 

[Salmonsaladsandwich]

Ooh! Great find! Pretty sure it's actually a polyphemus moth. (My personal favorite species.) If it hatches next spring and turns out to be a female, you can put it outside in a screen cage and she'll attract males from miles around. The larvae eat fresh oak and birch leaves.

 

[Shade of Eclipse]

Definitely looks like some sort of Saturniid. It's not likely to be anything under Hyalophora since it's so small. If the cocoon is composed of a single, thin layer of silk, it might be a luna moth. If it's double-walled, tough, and thick, it might be a polyphemus or one of the other medium-sized, cocoon-forming moths in the family Saturniidae.

 

[Ratmosphere]

It was super hard to even try and get open! If it's a Polyphemus moth, it's awesome because I never hatched one of these. I'd probably get really good pictures too.

 

[Salmonsaladsandwich]

Definitely looks like some sort of Saturniid. It's not likely to be anything under Hyalophora since it's so small. If the cocoon is composed of a single, thin layer of silk, it might be a luna moth. If it's double-walled, tough, and thick, it might be a polyphemus or one of the other medium-sized, cocoon-forming moths in the family Saturniidae.

He mentioned that it was still hanging from a branch, so it's almost certainly a Polyphemus. Lunas crawl to the ground before spinning a cocoon. The color and texture of the silk and the fact that it's difficult to get open also suggest polyphemus.
I would not recommend trying to cut the cocoon open if it still has to overwinter. Just be patient.